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<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      // 从以下学员名单中随机选出4个学员：

      let arr = [
        '鹿晗',
        '王俊凯',
        '蔡徐坤',
        '彭于晏',
        '周杰伦',
        '刘德华',
        '赵本山',
      ]
      let arr1 = []
      for (let i = 0; i < 4; i++) {
        let num = Math.floor(Math.random() * arr.length)
        if (arr1.indexOf(arr[num]) === -1) {
          arr1.push(arr[num])
        } else {
          i--
        }
      }
      console.log(arr1)
      // ​	注意：不要有重复的学员（封装函数）
    </script>
  </body>
</html>
